Source Code Management, Git, and GitHub are essential skills for developers, cloud engineers, and DevOps engineers.
Although these terms are connected, they have different purposes:
- SCM is the process
- Git is the version-control tool
- GitHub is the online collaboration platform
What Is Source Code Management?
Source Code Management, or SCM, is the process of tracking, organizing, and controlling changes made to source code and other project files.
SCM helps teams:
- Maintain code history
- Identify who changed the code
- Recover older versions
- Work on multiple features
- Merge changes safely
- Collaborate without overwriting each other’s work
Version-control systems maintain a history of project changes so earlier versions can be reviewed or recovered.
What Is Git?
Git is a free, distributed version-control system used to manage code changes.
Git normally runs on a developer’s local computer. Because it is distributed, each developer can have a local copy of the repository and its history.
Git can track:
- Application source code
- Infrastructure-as-Code files
- Configuration files
- Automation scripts
- Documentation
A Git commit records a project snapshot at a particular point in its history.
What Is GitHub?
GitHub is an online platform used to host Git repositories.
It adds collaboration features such as:
- Remote repositories
- Pull requests
- Code reviews
- Issues
- Access controls
- Automated workflow checks
Git performs version control locally, while GitHub helps teams store, share, review, and merge Git-managed projects online.
SCM vs. Git vs. GitHub
| Technology | Meaning | Primary purpose |
|---|---|---|
| SCM | Source Code Management | Complete code-management process |
| Git | Version-control tool | Tracks file changes and project history |
| GitHub | Git hosting platform | Stores repositories and supports collaboration |
The easiest way to remember the relationship is:
SCM = Process
Git = Tool
GitHub = Online Platform
How the Git Workflow Works
Git uses four important areas:
1. Workspace
The workspace is the project folder where you create, modify, or delete files.
2. Staging Area
The staging area contains the changes selected for the next commit.
git add filename
3. Local Repository
The local repository stores commits and project history on your computer.
git commit -m "Add login feature"
4. Remote Repository
The remote repository is the shared project hosted on GitHub.
git push origin main
The complete workflow is:
Workspace
↓ git add
Staging Area
↓ git commit
Local Repository
↓ git push
GitHub Repository
Essential Git Commands
# Create a repository
git init
# Download an existing repository
git clone repository-url
# Check changed files
git status
# Stage changes
git add .
# Save changes locally
git commit -m "Describe the change"
# View commit history
git log --oneline
# Download remote changes
git pull origin main
# Upload local commits
git push origin main
git init creates a new local repository, while git clone downloads an existing repository and its history.
What Is a Git Branch?
A branch is an independent line of development.
Developers use branches to work on new features or bug fixes without directly changing the stable main branch.
git switch -c feature-login
After completing the work:
git add .
git commit -m "Add login feature"
git push origin feature-login
Branches allow changes to be developed and tested separately before they are merged.
What Is a Pull Request?
A Pull Request, or PR, asks the team to review and merge changes from one GitHub branch into another.
A real company workflow normally looks like this:
Create branch
↓
Make changes
↓
Commit changes
↓
Push branch to GitHub
↓
Create Pull Request
↓
Code review and automated checks
↓
Merge into main
Pull requests help teams discuss changes, review code, run automated checks, and maintain an approval history.
What Is a Merge Conflict?
A merge conflict happens when Git cannot automatically combine overlapping changes.
For example, two developers may modify the same lines of the same file differently.
To resolve the conflict:
- Open the conflicted file.
- Select the correct content.
- Remove the conflict markers.
- Stage the resolved file.
- Commit the resolution.
git add filename
git commit -m "Resolve merge conflict"
Separate feature branches, small commits, regular synchronization, and team communication can reduce conflicts.
What Is .gitignore?
The .gitignore file tells Git which files and directories should not be tracked.
Common examples include:
*.log
.env
build/
node_modules/
Never commit passwords, private keys, access tokens, or other secrets to GitHub.
Why Git and GitHub Matter in DevOps
Git is commonly used as the starting point of a CI/CD workflow.
Developer pushes code
↓
GitHub receives the changes
↓
CI/CD pipeline starts
↓
Application is built and tested
↓
Application is deployed
Tools such as Jenkins, GitHub Actions, AWS CodePipeline, and Azure Pipelines can start automated workflows after code changes are pushed.
DevOps engineers also use Git to manage:
- Terraform configurations
- Ansible playbooks
- Kubernetes manifests
- Dockerfiles
- CI/CD pipeline files
- Shell and Python scripts
Important Interview Questions
What is SCM?
SCM is the practice of tracking, organizing, and controlling source-code changes throughout the development lifecycle.
What is the difference between Git and GitHub?
Git is a distributed version-control tool. GitHub is an online platform used to host Git repositories and support team collaboration.
Explain the Git workflow.
Changes move from the workspace to the staging area using git add, to the local repository using git commit, and to GitHub using git push.
What is a Git branch?
A branch is an independent line of development used to work on a feature or fix without directly affecting the stable branch.
What is a Pull Request?
A Pull Request requests the review and merging of changes from one remote branch into another.
Beginner Practice Task
Create a small GitHub project and complete this workflow:
- Create a repository.
- Clone it locally.
- Create a feature branch.
- Add or edit a file.
- Stage and commit the changes.
- Push the feature branch.
- Create a Pull Request.
- Review and merge it.
This single exercise covers the most important Git and GitHub skills needed for beginner projects and interviews.
Final Summary
Source Code Management is the complete process of controlling code changes. Git tracks versions and project history. GitHub stores Git repositories online and enables team collaboration.
Remember:
SCM = Process
Git = Version-control tool
GitHub = Repository hosting and collaboration platform